They are the Shadows, or "Red Eyes" as they are often called. Dark creatures, guided by the dark power, without conscience or soul and only aiming to hunt the "Snaps". To rip their heads off and steal their souls.
Thus a gloomy hole opened. A door to the underworld, the world of the shadows. The shadows hunted ruthlessly, without feelings or remorse. They are free of ethics, only ever following the dark power. They are soulless, determinated to hunt everyone until even the last Snap will be eaten and all souls belong to the Shadows. Nobody knows why the hole opened up so the Shadows came to the underworld. There are rumors, some believe the Shadows are led by a ruler, others speak of the doom of the Snaps' world, as the high priests had already predicted centuries ago.

By a bite to the head the Snaps die. By this the Shadows pull out the Snaps' soul and thus gain their force of life. Only a soulless body remains. The Snaps know of their doom and try everything to defend themselves - desperately they try to kill the Shadows, try to survive...